1. Field of the Invention
The present invention relates to an image forming apparatus that forms an image on a recording medium. In particular, the present invention relates to an image reading apparatus that supports both of a flow reading method and an original fixing method and has a size that is smaller than that of a conventional one, and relates to an image forming apparatus equipped with this image reading apparatus. Also, the present invention relates to an image reading apparatus that is capable of increasing productivity by preventing the occurrence of a time that is unnecessarily consumed to move an image reading means, and relates to an image forming apparatus equipped with this image reading apparatus.
2. Related Background Art
Conventionally, there has been used an image forming apparatus that reads an image recorded on an original (reads the original) and forms this read image on a recording medium such as recording paper. As a method for reading the original, there have been known so-called flow reading method and original fixing method.
With the flow reading method, a contact image sensor (hereinafter referred to as the xe2x80x9cCISxe2x80x9d) or the like for reading an original is fixed below an original base glass and the original is moved to pass through a region (a reading region) of this original base glass above the CIS, thereby reading the original using the CIS. On the other hand, with the original fixing method, an original is abutted against an original abutting board formed in the vicinity of one end portion of the original base glass, and the original is placed on the original base glass. The CIS is moved in a predetermined reading direction under this condition, thereby reading the original.
Image forming apparatuses that are capable of performing the flow reading method are classified into a type where a conveying member for conveying an original is arranged on the entire upper surface of an original base glass and a type where a sheet feeding unit for feeding an original to a reading region is arranged in one end portion of an original base glass. In the case of the type where there is used this sheet feeding unit, it is not required to arrange a conveying member on the entire upper surface of the original base glass, whereby weight reduction is realized.
A conventional example of the image forming apparatus of the type where the sheet feeding unit described above is used will be described with reference to FIG. 10.
FIG. 10 is a schematic diagram showing an example of the conventional image forming apparatus.
The image forming apparatus 10 is broadly divided into a reading portion 20 for reading an original and an image forming portion 100 for forming an image read by this reading portion 20 on a recording medium.
The reading portion 20 includes an automatic original feeding unit 30 having an original placing tray 32 on which an original is placed, a plurality of conveying rollers 34 for conveying the original placed on the original placing tray 32 to a reading region 22 in which the original is to be read, and an original discharging tray 36 on which the original having passed through the reading region 22 is placed. In the reading region 22, there is arranged a platen glass 24 above which the original passes. Also, a CIS 26 is arranged below the platen glass 24. The original placed on the original placing tray 32 is fed to the reading region 22 by the plurality of conveying rollers 34, is read by the CIS 26 while passing through the reading region 22, and is discharged to the original discharging tray 36 while being guided by a conveying guide base 38.
The image forming apparatus 10 is also equipped with an original base glass 40 for fixing and reading an original. Also, an original abutting board 42, against which an original placed on the original base glass 40 is abutted, is arranged in the vicinity of one end portion of the original base glass 40. In the case where the original is read with the original fixing method described above, a user abuts the original against the original abutting board 42 to position the original on the original base glass 40, and the original is read by moving the CIS 26 in a reading direction (a direction indicated by an arrow E).
The original read with the flow reading method or the original fixing method in the manner described above is formed on a recording medium in the image forming portion 100 arranged below the original base glass 40. A construction of this image forming portion 100 will be described later with reference to FIG. 10.
In the image forming apparatus 10 described above, the conveying guide base 38 becomes an indispensable construction element in the case of the flow reading method and the original abutting board 42 becomes an indispensable construction element in the case of the original fixing method. The conveying guide base 38 and the platen glass 24 are arranged outside of the original abutting board 42 so as to avoid the original abutting board 42. Consequently, the platen glass 24 for performing a flow reading operation is provided separately from the original base glass 40, thereby the size of the image forming apparatus 10 is increased accordingly.
Also, in a conventional image reading apparatus that reads an image of an original fed by such an automatic original feeding apparatus and in an image forming apparatus equipped with this image reading apparatus, an image reading unit 1106 is ordinarily positioned at a stand-by position for performing a leftward fixed reading operation indicated by a broken line in FIG. 11. In the case where a flow reading operation is performed, it is required to move the image reading unit from this stand-by position to a rightward predetermined reading position indicated by a solid line in this drawing. Consequently, in the case where a flow reading operation is performed, a redundant time is consumed to move the image reading unit 1106 from the stand-by position to the reading position, which elongates an image reading operation start time for the first sheet.
In view of this problem, in order to shorten the image reading operation start time for the first sheet, for instance, there is proposed a construction where before a user performs an operation to designate the start of a reading operation, when an original S is placed on an original placing tray 1102 of the automatic original feeding apparatus, a sensor 1104 detects this situation and the image reading unit 1106 starts to move from a stand-by position to a reading position in advance on the basis of a detection signal from this sensor 1104.
However, with this method, once the original S is set on the original placing tray 1102, the image reading unit 1106 starts to move. Consequently, in the case where the user of the apparatus erroneously places an original on the original placing tray 1102 and the original should be placed on an original base glass 1127, or in the case where a reading operation is performed by directly placing the original S on the original base glass 1127 after an original reading operation that uses the automatic original feeding apparatus is performed, it becomes impossible to start the reading operation until the image reading unit 1106 returns to the stand-by position.
That is, there occurs a time that is unnecessarily consumed to move the image reading unit 1106. Also, in the case where there occurs such a time that is unnecessarily consumed to move the image reading unit, the productivity of the image forming apparatus is decreased.
In view of the circumstances described above, an object of the present invention is to provide an image forming apparatus that supports both of a flow reading method and an original fixing method and also has a size that is smaller than that of a conventional one.
Also, the present invention has been made in view of the stated current circumstances, and another object of the present invention is to provide an image reading apparatus that is capable of increasing productivity by preventing the occurrence of a time that is unnecessarily consumed to move a reading unit (an image reading means), and an image forming apparatus equipped with this image reading apparatus.
In order to achieve the above-mentioned object, according to the present invention, there is provided an image forming apparatus including an original base glass for which a predetermined image reading region is formed and on which an original is placed, image reading means that is arranged below the original base glass and reads an image of the original, and an original automatic conveying apparatus that conveys the original to the image reading region,
the image forming apparatus forming the read image on a recording medium by reading the image of the original by selecting one of an original fixing scanning mode and an image flow reading scanning mode, the original fixing scanning mode being a mode with which the original is placed on the original base glass and the image of the original is read by having the image reading means perform scanning in a predetermined scanning direction below the original base glass, and the image flow reading scanning mode being a mode with which the image reading means is set to stay below the image reading region and the image of the original is read using the image reading means in the image reading region by conveying the original to the image reading region using the original automatic conveying apparatus,
the image forming apparatus characterized by comprising:
(1) an abutting member which is formed in the vicinity of one end portion of the original base glass and against which the original placed on the original base glass is abutted when the original fixing scanning mode is selected; and
(2) a conveying guide base that is formed on the other end portion side of the original base glass opposite to the abutting member and guides the original conveyed to the image reading region by the original automatic conveying apparatus to a predetermined sheet discharging tray.
In this case,
(3) at least one of the abutting member and the conveying guide base may be formed integrally with an original base frame to which the original base glass is fixed.
Also,
(4) in the conveying guide base,
(4-1) the conveying guide base may be formed integrally with the original base frame to which the original base glass is fixed, and
(4-2) a position, at which the original base glass may be fixed, is determined by abutment of the original base glass against the original base frame when the original base glass is fixed to the original base frame.
Further, the image forming apparatus may comprise
(5) a photosensitive drum on which a developed image of an image read by the image reading means is formed, and a fixing device that fixes the developed image on the recording medium conveyed from the photosensitive drum.
(6) The original base glass may have the image reading region formed in one end portion thereof on a side opposite to the fixing device with the photosensitive drum being sandwiched therebetween.
(7) The image reading means may stay below the image reading region when the image flow reading scanning mode is selected.
Still further,
(8) the original base glass may include the image reading region that is formed to be used in the image flow reading scanning mode, and the original glass is placed on the original base when the original fixing scanning mode is selected.
Also, the present invention is an image reading apparatus that includes an image reading means for reading an image of an original, that reads the image of the original by moving the image reading means from a stand-by position along a platen glass when the original is placed on the platen glass, and that reads the image of the original under a condition where the image reading means stays at a predetermined reading position when the original is fed from an automatic original feeding apparatus. The image reading apparatus according to the present invention is characterized in that: a detecting means for detecting that the original is placed on an original placing means provided for the automatic original feeding apparatus, an image reading operation start means that is operated to start an image reading operation, and a position control means that moves the image reading means from the stand-by position to the predetermined reading position before the original is fed by the automatic original feeding apparatus are provided; and if a detection signal is inputted from the detecting means when the image reading operation start means is operated, the position control means moves the image reading means from the stand-by position to the predetermined reading position.
Also, the present invention is characterized by that when no detection signal is inputted from the detecting means, the position control means judges that the image reading is finished and moves the image reading means from the predetermined reading position to the stand-by position.
As described above, in the image forming apparatus of the present invention, an original abutting member, against which the original placed on the original base glass is abutted, is formed in the vicinity of one end portion of the original base glass. In the case where the conveying guide base is formed in the vicinity of the other end portion of the original base glass on a side opposite to the one end portion, an automatic original feeding unit can be arranged in the vicinity of the other end portion of the original base glass. This makes it possible to widen the original base glass (or to arrange a small original base glass separately from the original base glass), thereby reducing the size of the original base frame in comparison with a construction where the automatic original feeding unit is arranged in the vicinity of the one end portion of the original base glass. As a result, it becomes possible to reduce the size of the original base frame and to reduce the size of the image forming apparatus accordingly.
Here, in the case where at least one of the abutting member and the conveying guide base is formed integrally with the original base frame to which the original base glass is fixed, it is possible to produce these construction elements without difficulty and also to reduce the number of components.
Also, in the case where the conveying guide base is formed integrally with the original base frame to which the original base glass is fixed and the position, at which the original base glass is fixed, is determined by the abutment of the original base glass against the original base frame when the original base glass is fixed to the original base frame, the conveying guide base doubles as a member for positioning the original base glass and the number of components can be reduced accordingly.
Further, there are provided a photosensitive drum, on which a developed image of an image read by the image reading means is formed, and a fixing device that fixes the developed image on a recording medium conveyed from the photosensitive drum. The image reading region is formed in one end portion of the original base glass on a side opposite to the fixing device with the photosensitive drum being sandwiched therebetween. In the case where the image reading means stays below the image reading region because the image flow reading scanning mode is selected, the image reading region is formed in the one end portion of the original base glass on a side opposite to the fixing device with the photosensitive drum being sandwiched therebetween. Accordingly, the image reading means is separated from the fixing device in the image flow reading scanning mode. Consequently, the image reading means is hardly influenced by heat generated by the fixing device. As a result, even if the image reading means is vulnerable to heat, it becomes unnecessary to provide a cooling apparatus or the like that cools this image reading means and thereby the number of components can be reduced accordingly. As a result, it becomes possible to reduce the size of the image forming apparatus.
Further, in the case where the original base glass includes the image reading region formed to be used in the image flow reading scanning mode and an original is placed on the original base glass when the original fixing scanning mode is selected, a single original base glass is commonly used in both of the image flow reading scanning mode and the original fixing scanning mode, which means that it is not required to use two original base glasses. As a result, it becomes possible to further reduce the number of components accordingly and to reduce the size of the image forming apparatus.
Also, with the present invention, in the case where an original is placed on the original placing means when the image reading operation start means is operated to start an operation for reading an image of an original fed from the automatic original feeding apparatus, it becomes possible to prevent the occurrence of a time that is unnecessarily consumed to move the image reading means and to increase productivity by moving the image reading means from the stand-by position to the predetermined reading position before the original is fed.